October 20, 1994|DAVID HALDANE | David Haldane is a member of the Times Orange County Edition staff who contributes regularly to OC Live!

Few sport divers ever descend below 100 feet.

Such depths are generally avoided because of the strange and dangerous things that can happen--most notably nitrogen narcosis, or "rapture of the deep," and the bends, a painful and potentially fatal condition brought on by coming up too fast after staying too deep too long.

Despite those dangers--or perhaps because of them--a group of fellow divers and I recently took a 165-foot dive. Pinching our noses all the way down, we forced air through our eustachian tubes to prevent the pressure from rupturing our eardrums. At about 120 feet, we began feeling the first twinges of rapture; at maximum depth, we were in full-blown ecstasy. To avoid getting the bends, we made several long decompression stops on the way up.

Sound risky? Ironically, it was the safest dive I've ever made because we never entered the water. The dive took place in the Catalina Hyperbaric Chamber.

The chamber is there to treat injured divers, but we were there as part of a rescue course to learn more about it. Owned and operated by USC, the 26-foot-long by 9-foot-wide steel tank--also known as a re-compression chamber--sits in a hangar at the Wrigley Marine Science Center on the isthmus of Catalina Island.

There, two main types of diving injuries are treated. The first is the bends, in which excessive nitrogen in the blood expands into bubbles. The result is always painful, often crippling and sometimes fatal. The second is air embolism, which happens when a scuba diver ascends while holding his breath or experiencing some sort of blockage that prevents the air in his lungs from escaping. As the diver comes up, the air expands, eventually rupturing the tiny air sacs in the lungs and escaping into the blood.

The treatment for both conditions is to put the patient in the hyperbaric chamber and pump enough air into it to increase the pressure to the equivalent of a depth of 60 to 165 feet. The ailing diver is then, in effect, "brought up" at a rate slow enough for the nitrogen or air bubbles to dissolve.

This treatment has been administered to 11 divers this year--475 since the Catalina chamber opened 20 years ago. Then there are the dozens of uninjured divers who, for $20 a head, have experienced something called a "chamber dive."

"Re-compression is a vital part of rescue," Sam Miller IV told me and a dozen other divers from the Sports Chalet in Huntington Beach. "The chamber serves a vital function in the dive community, and this gives them a hands-on experience."

We had another reason for being here. Simply put, it was to experience the strange effects of nitrogen narcosis, that build-up of gas in the brain that gives divers below 100 feet such odd sensations. If we could learn to recognize the rapture in a controlled environment, we would be better equipped to deal with it in the ocean, where sound judgment can mean survival.

Crowding into the chamber after a briefing outside, six of us waited in anticipation as the countdown began. Suddenly the huge compressor jolted awake as the chamber began filling with air.

I experienced a moment of fear. Now there was no turning back. By the time the depth gauge read 10 feet, the fear had subsided. Holding my nose to equalize the pressure behind my ear drums, I rode the thing on down.

Around 120 feet, I had the first pleasant symptoms of nitrogen narcosis. Sweating in my T-shirt, I suddenly felt light-headed, a sensation that increased as did the pressure. By the time the compressor shut off at 165 feet, we were all thoroughly zonked.

Experiencing the rapture of the deep is like being drunk or on drugs. You feel a kind of euphoria, a thoroughly unreasonable sense of well-being. It is this feeling of imperviousness to danger, of course, that makes the condition so dangerous to divers. Imagining themselves invincible, divers can make fatal mistakes.

Ensconced in the safety of the chamber, we spent our six minutes at the bottom telling jokes and trying to put the square pegs of a baby's puzzle into their round holes. Everything seemed incredibly funny, an illusion undoubtedly enhanced by the fact that the pressure on our throats made us all sound like Mickey Mouse.

When it was time to surface, nobody wanted to go. As pressure decreases, the effects of nitrogen disappear almost as quickly as they come on. Within a few minutes, we were all feeling normal again.

By the time the chamber's airtight hatch was disengaged, we had spent 44 minutes under pressure--a period that seemed much shorter. And though we had not traveled an inch, it seemed to all of us that we had been far away.

"That was great," said Suzanne Pefferman, a 22-year-old UC Irvine student. "It's valuable to experience the nitrogen effect and be able to recognize it."